Astroblog

Obscured by Clouds. The rough and ready blog of a cloud benighted biologist and amateur astronomer. Astroblog will cover my interests in astronomy, biology and Life, the Universe and Everything.

Wednesday, November 30, 2005

This weeks fuzzy planet photos are ...

Venus and Mars. They are both shown to the same scale. They aren't the best images, due to lots of turbulence (the stars were twinkling furiously again tonight, not as much as last night, but still pretty strong). Mars looks a bit yellower compared to the last image, apparently there is a bit of a dust storm going on at the moment. Mars has visibly shrunk (compare the previous images) and is a mere 17 arcseconds in diameter. Venus is a swelling crescent, and will get startlingly bigger in the coming weeks. NASA science reckon you can see Venus as a crescent in binoculars, but you would need at least 10x50's with GOOD optics (other wise the glare will wipe out all crescentness).

PT, the place Science refers its readers to...

You may know that I occasionaly write biology-based articles for the Panda's Thumb, an evolutionary biology blog that also serves to educate people about Intelligent Design creationism. When I finish my Sky&Space contribution I have 4 PT posts to finish, keep a look out for them. The Panda's Thumb got mentioned very favorably in the journal Science's netwatch section. When one of the most prestigious science journals links to you, you know you must be doing something right.

Searching for Venus's Shadow.

A few days ago I linked to this fantastic page by Pete Lawrence on photographing Venus's shadow. Now NASA science has highlighted the story too. It turns out that between now (Tuesday November 29) and Saturday December 3 is the best time to observe Venus shadows. Venus is magnitude -4.7, very nearly at its brightest, and there is no Moon. After December 3 the Moon is in the evening sky and all you will see is shadows from Moonlight. To see shadows from Venus you will need a dark sky site with a level horizon and no interfering artifical lights. You will also need to look after astronomical twilight (that's about 21:57 ACDST, 22:14 AEDST, Venus sets an hour later), when the sky is dark but Venus is still up. you will also need a white screen of some sort to see a shadow against. Then turn your back on Venus, hold an object such as your hand in front of the screeen, and if your eyes are dark adapted you should see a shadow.

Sunday December 4 the Moon and Venus are close together, should make a nice photo shot.

Monday, November 28, 2005

Martian Anniversary

Image Credit JPL/NASAThe rover Spirit has been on Mars for one Martian year (as of November 20, so this is a little late) and Opportunity will have completed its first Martian year on December 12. In celebration NASA have released simulation images showing the Rovers on Mars (3D models of the rovers mapped onto real images of the Martian surface), why not take in the slide show. They also have a summary of Spirits year on Mars. Go have a look.

Twinkle, Twinkle little star

Seeing stars twinkling is a special experience, somehow we expect to see stars twinkle, and feel a bit cheated if thay don't. Of course the same twinkling heralds atmospheric trubulence which makes for lousy planetary viewing, where you image dances around like water on a stove. Tonight I just went out to have my evening peek at the stars, and they were doing the most amazing twinkling I can rememeber seeing, a real stellar jitterbug. It almost looked like a speeded up Hollywood special effect. Guess I'm not taking the scope out then.

IDiocy in our papers

Intelligent design, the idea that if we can't describe the evolution of a given biological system on a mutation by mutation basis, then something, somewhere, somehow designed that biological system via unknown processes, has hit Australian newspapers again. First we have the Campus crusade for Christ spending upwards of $65,000 to distribute 3000 slick ID creationism DVD's to schools (but they are not trying to promote teaching ID in schools, oh no). Then we had the Age publishing an opinion piece by Peter Coghlan that more or less uncritically accepts Behe's statement that bacterial flagella can't evolve and suggests that ID could be raised in high school biology classes. As I have written a book chapter describing how bacterial flagella may have evolved (and collaborating on a major review of the subject), I fired off a letter to the Age. It didn't get published, nor did any of the other letters I knew that were sent get published. In the end only one rather anodyne letter that did not address major issues of fact was published. Here is the letter I sent.

Dear Sir/Madam

Peter Coghlan's essay (God v science? Age 23//11/05) interested me, as I have written a book chapter on what Dr. Behe says can't occur, the evolution of bacterial flagella.

IC depends on our ignorance of structures, not on our understanding of them. These examples show one reason why Intelligent Design is not science. While individual claims about flagella and clotting systems have been refuted, these refutations are ignored by ID proponents who continue as before.

Dr. Coghlan suggests this debate could be raised in senior high schools. But students barely have enough time to learn the core principles of biology. If we waste their time with a debate arising simply because ID proponents haven't read the relevant scientific literature, we do the students a grave disservice.

Ian Musgrave has authored a chapter on the evolution of the bacterial flagella in "Why Intelligent Design Fails" Rutgers University Press, 2005

I didn't expect my letter to get in. Back in August the Religious editor of the Age published an opinion piece lambasting scientists for "scientific fundamentalism". It also claimed ID was scientific and not religiously motivated. There were numerous errors of fact in that article, and I and others fired off letters pointing this out. None got published. I had an amiable correspondence with the Religion Editor, sent him my chapter, and he promised to pass on my letter pointing out the errors of fact to the letters editor. I sent it off to him ... and nothing happened. For the record, here is the letter about the August article.

In the Age Opinion page of 18 August, Religion Editor Barney Zwartz asks for a proper scientific debate on Intelligent Design Creationism. Scientists will welcome that, when the Intelligent Design Creationists produce some science, instead of recycling failed arguments and producing fancy DVD's. Almost every item of alleged fact in Mr. Zwartz's article is wrong. Intelligent Design was a carefully crafted response of the creationist movement after a series of court defeats prevented its teaching in US schools. Michael Behe is a Catholic, not a non-Christian, and he first presented his ideas in a creationist textbook. Most of the key players in the ID creationist movement are not scientists, but lawyers or philosophers. Furthermore, they are all conservative Christians who have openly spoken of their theological agendas. Rick Sternberg was not hounded out of his job as editor; he had already come to the end of his term as editor and retired. These are all matters of fact, and can be readily checked. The concern about ID creationism is because its proponents want it taught as science. The scientific opposition is due to real concern over the subversion of the process of science to teach something that has no evidential support.

That letter only covered the most significant errors of fact. But no correction to even these errors was ever published. Now there are readers of the Age who seriously think that Behe is a non-Christian. The general public, listening to our media, will be under the impression that ID is science, and that it is being kept out by a conspiracy of scientific fundamentalists.

"A lie can circle the world while Truth is putting its boots on" writes Terry Prachette in ÂThe TruthÂ. This adage has never been more true than in the recent Australian encounters with Intelligent Design Creationism. This is how pseudoscience wins, but taking the issue to the media. The ID proponents can say all the nonsense they like, and real scientists can't get a word in because editors have other priorities that ensuring that nonsense gets corrected. Ordinary scientists are shut out by editors who think they have published enough articles on the subject.

In Terry Prachettes fantasy, a man with a printing press prints the truth against all odds, sadly, in Australia, getting the truth out remains a fantasy.

Saturday, November 26, 2005

Hayabusa has landed!

Image credit JAXA.Plucky little Hayabusa keeps on keeping on. Despite losing most of it gyroscopes, losing the robot probe Minerva and being plagued with communications problems, Hayabusa succeeded in touching down on the asteroid Itokawa. This is the first probe ever to land on an asteroid, and is a ground breaking feat. Hayabusa didn't take any surface samples this time, but there will be a new attempt on 7.00 pm November 26th (Japanese Standard time, UTC +9, so that is around 9.00 pm AEDST and 8.30 pm ACDST). Check out the JAXA site to see if they do live blogging this time.

A problem I wouldn’t mind

Image by Bryn JonesThe Antarctic in winter would seem to be a good place to watch the stars, the Antarctic plateau is high, and the air is very dry and unpolluted, there is no light pollution and 24hour darkness is a pretty good bonus. Unfortunately, visual wavelength telescopes at the South Pole have to contend with aurora. Yes, that’s right, frequent aurora disrupt visual observing. I feel so sorry for them (the original article is at Nature, but you need to be a subsrcriber).

Friday, November 25, 2005

Morning ISS

Thanks to the ISS transit prediction service I got up in the predawn twilight to watch the International Space Station glide past the Moon. All but the brightest stars were fading fast when I saw the ISS bright overhead, it glided gently through the sky and then sailed across the Moon, almost dead on the terminator.

Thursday, November 24, 2005

Lazing on a Sunny Afternoon.

Image credit NSA/JPL Sunspot 822 is shrinking fast, and is no longer a potential source of aurora. However you still have a chance to catch it using safe solar projection techniques. On the past weekend, Chez Reynella was doing its usual couch potato thing, distributing growing boxes for Trees for Life (that was irony, by the way). I was trying to mark a pile of exam papers, so I was relegated to making cups of tea, hauling boxes of mulch and trying to stop the kids killing themselves while the Bettdeckererschnappender weisle explained to people how to plant and look after 20 native plant seedlings. In my tooing and froing I decided it would be a good time for some more footpath astronomy, so I set up my elderly refractor to do solar projection. Sadly, everyone seemed more interested in seedlings rather than sunspots, so the rig sat out all lonely. I took a few shots to show people my ultra-sophisticated set-up (there’s that irony again).

Here is a shot of the Sun as projected through a 50 mm refractor with a 6 mm objective (click the image to enlarge it). You can clearly see the major spot and its umbra, the subsidiary spot, and if you squint you can see the trail of small spots connecting the two. The picture doesn’t do the image justice. The spots were nicely in focus on the screen, but I just couldn’t get the camera to focus on them. This was at least in part due to the wind which was whipping the rig around. (the strange shadows are gunk on the main lens, have to clean that up). This was a case where pen-and-pecil sketching beat photography.

So here is the rig. The scope sunshield is made of a Pizza box lid (no expense spared). The projector system is two sets of dowling connected at right angles (glued and taped). A small square of stiff white cardboard was taped to the one arm of the dowling, and the other was taped to the body of the scope. One day when at the hardware store I will pick up some clamps to hold the dowling on properly, but tape is a quick and dirty solution.

Except in wind. I used a similar setup to watch the transit of Venus while my reflector was festooned with camera gear, and it worked perfectly. But this day there was a fair bit of wind, which played merry havoc with the projection screen, so it wouldn’t stay straight. Hopefully I’ll have something better rigged up next time.

Now here is the binocular setup. I’ve mounted the binoculars on a camera tripod (use old binoculars just in case the heat causes the lens to crack). Make sure you secure the binoculars firmly to the tripod (you can go to the hardware and get a bit of wood, a long screw and butterfly nut to make a clamp) or they will fall off and smash at an inconvenient moment. I put foil over one lens while aligning the binoculars, then I use the handy Pizza box as a sunshield. Now, you may say, since I can’t look at the sun, how the heck can I align my scope or binoculars on the Sun. You use the shadow of the scope or binoculars. With the sunshield off you adjust the shadow of your scope or binoculars until it is of minimal size, then viola! The Suns image will appear, you can put the sunshield on and start observing.

This is my shot of the image formed by binocular projection. It's fairly lousy because the wind kept whipping away the screen i was using to project the image on. While not as good as the telescope projection image, you could still identify the major features.

The Horns of Venus

When Galileo turned his telescope to Venus, he saw that it went through phases like the Moon. In that one observation the geocentric solar system was shattered forever (okay, so Tycho tried to save the geocentric system by putting all the planets orbiting the Sun, and the Sun orbiting the earth, but the Ptolemaic system was gone forever). Above are my images of the phases of Venus, you can clearly see the increase an size and crescentness of Venus as time goes on. This is what I love about science generally, is that ordinary people can test out the foundational concepts and observations of science themselves. When I look at the pictures I've taken, I see more than wonky webcam shots, I see a revolution in thinking. I had a big discussion with a member of the ABC Science Matters discussion list about the role of "faith" in science, and the phases of Venus were an example I used of how you don't need to accept statements of Science on "faith", but can check them for yourselves. Admittedly, there are lots of things like particle physics it is hard for an amateur to test, but right now amateurs are imaging transiting exoplanets, so there is a lot you can do.

Tuesday, November 22, 2005

Stacking On

I shoot 2 second AVI’s at 30 frames per second with a QuickCam VC using Vega (gain setting 125, exposure time 3) and I use Registax 3.0.1.22 to select and stack the AVI frames. I manually remove bad frames, and use pretty plain vanilla settings for everything else (Linear wavelets, 1 step increments in layer 1 only, and I use a Lanczos filter). See the Registax 2.0 tutorial here (still applicable to Ver 3.0)

I don't know if this is specific to the Meade DSI, but they claim 50 images will get the quality to about 90%.

This is almost certainly true of the Meade DPI imager, but will depend of the quality of seeing. If seeing is not that flash, you may have to take more frames (and hand discard obviously bad frames). The lunar image to the right is a stack of 58 frames (I manually tossed two) in the original 320x120 format that the QC takes. It’s pretty good given there was a bit of turbulence about.

This image is a section of the above image expanded and processed in the same way as the Mars images. Still not bad but much muddier. This shows that I am pushing things to the limit with my setup.

A quick recap of stacking. Digital imaging has revolutionized astrophotography in ways we couldn’t imagine 10 years ago. With a traditional film camera, you need to expose an image for a modest length of time, bright Moonscapes don’t require much exposure time, but planetary images do require a bit of duration. During this time the atmosphere is jumping up and down and bouncing around. Your images end up looking smeared, not the crisp planetary views you see through your eyepiece. You need nights of exceptional clarity and stillness to get good images, even then you usually need to take more than one photo to get something respectable. The number of images you can take is limited by the amount of film you can afford, and at the end of the day you have one or two good images.

With digital imaging, you are limited by how much hard disk space you have. Taking 60 film shots a night is beyond my budget, but taking 600 digital images in a night is a snap. The other thing about taking multiple digital images is that you can stack them. Random noise cancels out, and the real image is reinforced. It also increases image depth, which is important in astrophotography. Stacking can produce stunning images, and with stacking amateur astronomers can produce images that were the province of professionals less than a decade ago. Of course, using an elderly webcam like I do, my pixel size is very limited compared to the newer webcams like the ToUCam. And no amount of stacking will compensate for out of focus images or poor collimation.

So how many images do you stack? The answer depends a lot on the noise in your camera. Webcams are rather noisy compared to dedicated imagers like the Meade DSI, or the Meade Lunar Planetary Imager. So you need to stack more with a webcam than a Meade imager. When conditions are bad you will need to stack more. For imaging the Moon and Jupiter, I’ve been using as few as 30 frames. The Moon images above were done with 58 frames as I said, and they look pretty cool (compare the expanded version above with Tom's Moon shot, they are not dissimilar, and have similar stacks). The Jupiter image was assembled as a stack of a mere 30 frames, the band structures are clear (and in the original you can see Jupiter’s Moons). My best Mars shot is shown at the same scale as Jupiter, and is a stack of around 45-50 frames (I had to toss quite a few, and as I said before, this was a good night). One problem is accurate registration. When the image is small and has few distinguishing features, it is harder to align then accurately. I could add on my 2x Barlow lens, but without a clock drive Mars would shoot out of frame so fast it would be hard getting any shots at all. To give you an idea of what some people will go to, this series of Mars shots was taken with an 8” SCT and represents a stack of 1200 frames per image! This amount of stacking is not untypical of the images created by QCUIAG enthusiasts.

So how much stacking? Unfortunately, you will have to experiment yourself. People with real imaging systems like the Meade DSI or LPI can go with the manufacturers recommendation. Webcam users? The more the merrier (to a limit, the QuickCam VC’s resolution is too poor for stacks of over a 100 frames to be of much use for small images like Mars).

Finally, the panel below is a comparison of images that I “just stacked” and those that I ruthlessly pruned of suspect frames. It would help if my eyesight was better. The 31/10 image improved substantially with pruning, the 31/10 image looks worse after pruning, and the other look only marginally better. Which goes to show that telescope conditions are still critical with all this fancy gadgetry.

Monday, November 21, 2005

My best Mars image yet!

I've found the way to get the best Mars shots, stay up past midnight marking exams, until Mars it at its highest, the wind is at its stillest, and the turbulence is at it lowest. This one actually looks like a planet, rather than a fuzzy semi deflated beachball, and has a more than passing resemblance to what Mars was predicted to look like. This is about as good as it gets, I'm limited by a number of things, pixel size, resolution of the stacking program, and the fact I don't have a clock drive. To get better images without buying new kit (must resist urge to buy ToUCam) I would have to stack more frames. Stacking multiple frames averages out the bad seeing and reinforces features that are consistent. I've stacked about 40 frames here, having tossed about 20 (and this was under good conditions). Many of the really nice webcam images you see have stacked over a 100 images, but 60 frames represents about 30 Meg for me, so I'm reluctant to take up more disk territory. Still, It doesn't look half bad. The purpose of this is not to skite, but to show what people can do with really simple and cheap gear.I've lined up a selection of my Mars shots here. Apart from the fact that the early ones are really wobbly (I should go back and restack, being ruthless in discarding, this might make a little bit of improvement), you can see that Mars is gradually diminishing, as it recedes from us. One night I might try and get Mars rotating, if I can stay awake that long.

Friday, November 18, 2005

Sunspot 822

Sunspot group 822 is now large enough to see with safe solar projection techniques, such as pinhole projection or binocular projection. The above image was taken using binocular projection. It is not the best as the Sun shone through a brief break in the clouds as it was setting and I didn't have time to set up a proper screen, so I whacked a bit of white paper on the water tank and grabbed a quick image (but distorted due to the angle of the Sun to the tank). Davep has some notes on seeing 822 using projection techniques.

822 has been firing off more M class flares, but it is too early to tell if they will head our way and produce aurora.

Venus and Nunki

If you looked into the western sky tonight, the "handle" of the "teapot" of Sagittarius would have looked odd. Venus was substituted for Nunki, the bright star in the handle. Actually, Nunki was still there, only 12' away (about a quarter of a Moon diameter away) and very hard to see in Venuses glare. In this image Nunki (sigma Sagittarii) is the dot to the right of Venus (the brightest dot in the field) in the thumbnail you can just see the other stars of the handle, they are easier to see tin the larger size version (click on the thumbnail to view)

Good News Week

Eldest One scored at or above the national and state benchmarks in the LAN tests. His readibng skill were nearly off scale (cause like his dad, he's a reading fanatic). Soccer Fan managed to recover from celebrating Australia's win over Uraguy to score a H2A for his honours (all four of my Uni Adelaide honours students have scored H2A's. Three are doing PhD's, two in my lab. They intend to form a band, the H2A band), Yah! Good result for hard work. Lone Lady (who is currently outnumbered by Y chromosome bearing students 3-1) has had a major experimental result, and looks like confirming a key hypothesis. Not a bad way to end the week. Now I can look forward to a weekend of exam marking. Whee!

Dione and Tethys, just amazing

What can I say, this image of Dione and Tethys across the rings of Saturn is just jaw droppingly amazing. If you want words, see this page for a description of what is going on and a link to a high resolution image. I'm just too stunned to write anything.

Monday, November 14, 2005

The Mountains of Creation

Image credit NASA/JPL-Caltech/L. Allen (Harvard-Smithsonian CfA)

Remember the iconic Pillars of Creation in the Eagle Nebula? Well the Spitzer Space Telescope has spotted something to put the pillars to shame. The Mountains of Creation are massive pillars of gas in an area called W5 in Cassiopeia. They are 10 times the area of the Pillars of the Eagle Nebula. The relentless radiation form a massive star is eroding cool, neutral hydrogen into these finger-like extensions. Within the pillars new stars are being born, revealed here by Spitzers IR imaging.

The really cool thing is that the (false) red colour is due to the absorbance of infrared light by complex organic molecules, the things that are important for life. It might be that these complex compounds will seed planets newly formed around these juvenile stars, possibly leading to life developing of these nascent worlds, and that these will be truly Mountains of Creation. See more at this page and at Toms astroblog.

The Sun stirs again

After weeks of quietness, where the Sun has had only a few, or sometimes no, Sunspots, this big blighter (822) appears. It has already fired off 2 C class and two M class flares, and it might be capable of more. If it stays active when it rotates to a more geoeffective position, it might result in aurora.

Yes, another Mars shot

This is probably my best Mars shot yet. Syrtis Major is clearly visible. Turbulence wasn't too bad, sky was clear but there was a little wind buffeting the scope at inconvienient times. Still, came out pretty well I think.

Sunday, November 13, 2005

Well, it's got a rocket in it.

When you have been up late cleaning up after your Smallest Ones second birthday, when you have a virus, when you have been woken at 2.00 am by Smallest one reacting to a surfeit of chocolate crackles (and have to strip off all the bed sheets and get them in the wash), and then repeat the performance when he vomits over you half an hour later, what should you do next? Sleep in? No[1], we get up, get on the train and go to the Adelaide Christmas pageant. The floats are made by local community groups, and it is all a bit cheesy, watching castles with fake snow go past to cheerful tunes about dashing through the snow ... on a bright and hot Australian spring day. But it is a local tradition, and refreshing in a sea of crass commercialism. And there was a rocket in it, so the kids liked it (and Santa as well, that was a bonus).

Footpath astronomy

What constellation is this? (click to enlarge) Test your knowledge of the sky and have a guess. The image was taken at 11.00 pm facing South (answer at bottom of post).

I have a cold. But I also have a boy turning two, so instead of doing the sensible thing and going to be early, I assisted in Smallest Ones birthday bash[1]. In the process I pointed out daytime Venus to some of the adults[2], who were pretty amazed to see a planet in daytime, and a "footpath astronomy" session started. Footpath astronomy seems to be breaking out all over at the moment. Top of the Lawn and Stuart have had footpath encounters.

Well, the footpath astronomy didn't start immediately, first I had to do the barbie (which is more complicated than it sounds when you have to keep the vege barbecue away from the carnivorous barbecue while keeping industrial quantities of kids sausages [which appear to be made of sawdust and wallpaper paste] coming) and then dark had to fall, which takes longer now that daylight saving is upon us. But after the barbie was over, the telescope was wheeled out to the delight of adults and children.

The waxing Moon was fairly high in the sky, so we turned to that first, the crater Copernicus with its terraces was visible in high relief. We could see the ridges in the lava fields of Mare Imbrium and the mountains threw long shadows towards the terminator. Everyone was smitten by the stark beauty of the scene. Even if the kids were smitten momentarily, before rushing off to their games. My kids are quite blase about the telescope, seeing as I wheel it out at the drop of a hat, and all camping trips have telescope accompaniment.

After the splendors of the Moon, we turned to crescent Venus, which impressed the adults, most hadn't realised that Venus had phases, and I explained the significance of that. After a bit of cleaning up we finally turned to Mars. Mars wasn't high (it was a kids party after all, no one was staying late), so once again our friend turbulence came along as well. However, we could clearly see the dark bands and Syrtis Major on the limb. The kids came out again for this. A small round dot is quite hard for kids to see, as they don't have a feel for how thing should look in a scope, but they did see it, and were amazed at seeing our sister world. The adults were pretty impressed at seeing any detail at all.

Soon everyone had to go home, the party had lots of good memories to go home with (including my cool mega bubble mixture), and the sky views were one part of that.

Oh, and the constellation? It's luminescent dye from those luminescent circlets they sell at fairs. We had a batch that leaked, and I shot the drops that glowed on our floor. It was facing south though :-)

[1] Anyone who says "Oh, how could you miss out on you little boys birthday" has never tried to deal with several boisterous children without a functioning nose or throat.[2] Man am I getting good at seeing Venus in the daylight. I no longer require the Moon as a "skymark" to find it. In the back yard I have several landmarks (posts an chimneys on the roof) which I can use to orient myself, and locate Venus pretty quickly. If you want to do it yourself, find a spot in you backyard where the sun is blocked from view in the early afternoon, and there is a good landmark (a tree or post). The wait for twilight, return to the same spot and note the position of Venus with respect to the landmark (you might want to use a ruler to get exact locations). You may want to check at various times as evening draws on, to be able to extrapolate Venuses position before sunset. Next day, return to the spot before Sunset, and look around the spot you have fixed with respect to the landmark. Venus should pop out at you fairly soon (make sure that the Sun is completely blocked from view to avoid eye damage)

Occultation of the Pleiades, November 16

On the evening of Wednesday 16 November the Moon will cover (occult) the Pleiades. This will be the last occultation of the Pleiades to be seen from Australia for some time, so it will be worthwhile to have a look at this one. The weather forecast seems alright for the night as well.

The bad news is that it won't be very spectacular. The occultation takes place during the full Moon, when the brightness of the Mooon will drown out all but the brightest stars. It will also be visible only from the eastern and central states, Western Australia will miss out completely. It also starts shortly after Moon rise in all states, so the Moon will be low to the horizon. Nonetheless, there are a couple of reasonably bright stars that get covered and uncovered (Alcyone, Maia and Electra, depending on exactly where you are observing from), and this should be visible in binoculars, as well as small telescopes (but it almost certainly won't be an unaided eye event, unless you have exceptional eyesight).

Occultation times for various cities (NOT in daylight saving time, so daylight saving staes will have to add an hour) can be found at the Southern Skywatch Occultation page.

Thursday, November 10, 2005

More Mercury

After some really nasty days of rain (suburbs just to the north of us were flooded), the skies cleared briefly to allow me a glimpse of Mercury near Antares. It will be similar to this again tommorow night. I've photoshopped Mercury and Antares a bit so they will show up on the thumb nail. Click the image for a larger size version where you can see Mercury clearly and the stars in the Scorpions tail. Venus is in the "Lid" of the "Teapot" of Sagittarius (the teapot is upside down for us Southern Hemispherians).

Showering will never be the same again

More daytime Venus

Walking through the campus to the train this afternoon, I noted that the sun was completely blocked by the Chemistry building (thanks for the new protein guys!). Idly I wondered if I could locate Venus this early in the afternoon, and without the handy Landmark of the Moon close by. So I located the Moon, found a spot roughly half way between where the Sun should have been and said Moon, and after a couple of seconds hunting Viola, there it was! Clear as a pin. I wonder if I can get a telescope shot in the daytime?

And this afternoon was glorious after all the rain (at least we didn't get flooded like so many suburbs), Mercury is quite bright and is edging up to Antares. Should look very nice in a couple of days.

My students certainly think I'm scary

I'm hardly scary at all, while to my dissapointment Wilkins and PZ are much scarier. Hey, I keep carnivourous plants and I answered "psychologist" as what I want to be when I grow up, how much scarier do you want?

Monday, November 07, 2005

Is there life on Mars?

The possibility of life on Mars has always fascinated us. There was Percival Lowell who interpreted Giovanni Schiaparelli's canalli to be water filled canals serving the Martian populace. The shifting dust patterns on Mars were interpreted as being due to seasonal changes in vegetation.

Then came the Martian meteorite ALH84001, there were traces of organic chemicals, life-like isotope ratios and what looked intriguingly like microfossils. After lots of debate most researchers think that ALH shoes no clear signs of Martian life, but there is still ongoing debate.

Finally there was the excess of atmospheric methane. We have come a long way from Barsoom, but excess methane is an important clue. Methane is broken down very rapidly, and if there is substantial methane in Mars's atmosphere, it must be being produced. Methane can be produced in one of two ways 1) volcanism or 2) Living things (on Earth, burping cows are a major source of atmospheric methane). Not only does Mars have more methane than expected, but the methane is higher in certain regions, regions which correlate with water in the ground and above surface water vapor. This suggests that the methane is not from volcanic activity. There was also the suggestion that there was a lot of formaldehyde in Mar's' atmosphere, since formaldehyde was generated from methane, that implied that there was a lot more methane than could be accounted for by volcanism. However, the interpretation of the infrared spectrum is still open to doubt.

New data from the NASA infrared telescope facility also suggests that volcanism may not account for Mars's methane. They found no evidence of sulfur dioxide in the atmosphere, suggesting very low rates of volcanic outgassing which could not account for the levels of methane. Now, it is too early to declare Mars a wildlife reserve yet, and there are a number of possible non-volcanic geological systems which might produce methane, but at the very least it indicates that we should keep up the search for life on Mars. Bacterial flatulence may not be as exciting as Banth tracks, but it might just be the clue that will lead us to the first extraterrestrial life.

Sunday, November 06, 2005

A Mars a Day

Makes you feel rather good. No idea what the turbulence was like, as the wind was buffeting the scope too much. Turned out an okay image though. I chose the wrong night to practice with different exposures.

Another shot of Mercury

Another shot of Mercury (I've labeled it this time for easy viewing. As before, click on the image for a larger size easy viewing version). Antares is just above Mercury, and on November 10 and 11 Mercury will be two fingerwidths from Antares. I didn't try any telescopic shots this night, icreams in front of the TV were calling.

Saturday, November 05, 2005

Daytime Venus

See that dot just up at the top righthand side. That's Venus, the unusual thing is that image was taken in daytime. Now, I have to tell you that this image is photoshopped to the max, that I have maximized every attribute to make Venus and the Moon stand out as more than vague "might bes" on the computer screen. But while imaging these things was a right royal pain, they were as obvious as canine genitalia to the unaided eye.

Venus is currently bright enough to see with the naked eye. But locating a not too bright dot in a field of bright blue can be difficult. If you have a guide, like the Moon, it can be a lot easier. At 6:30 pm ACST, the Sun was roughly 15 degrees from the local horizon. I used the house roof to obscure the Sun (always be very careful to avoid staring at the Sun to prevent damage to your eyes). Looked up about 40 degrees to find the Moon, which was a fairly obvious crescent, then 6 degrees above that (and slightly to the side) was a very obvious Venus.

You have a chance to find Venus easily in daylight tomorrow. Venus will be 5 degrees below the Moon. So an hour or so before the Sun sets, find a nice spot where the Sun itself is blocked from View, but there is a good clear northwest sky. Look up to about 3/4 of the way to the Zenith (70 degress or about 12 handspans) in a northwesterly direction and the crescent Moon should be obvious. Look below the Moon by about 4 finger widths (roughly 5 degrees) and Venus should be an obvious bright dot. Good Luck, and don't forget to avoid looking at the Sun.

Taurids for Guy Fawkes Night

Tonight (Saturday Nov 5) is Guy Fawkes Night. This celebrates the attempt of the Said Mr Fawkes to blow up the British Houses of parliament. This is usually celebrated with bonfires and fireworks. It was celebrated at one stage in Australia, but as November 5 is close to our Summer and bushfire season, fireworks were banned (as as the whole reason for Guy Fawkes night was fireworks, it rapidly passed out of folk memory). However, the sky might put on its own fireworks for us, in the form of Taurid fireballs. If you are out looking at Mars, send a bit of time looking out for meteors as well.

Planets in the scope

Well, Mercury didn't turn out too badly, given that I was shooting a few degrees above the neighbours roof and being mugged by mosquitoes. This image is a stack of 15 AVI frames. I shot 30 but had to throw half the frames away. This makes it unlikely that I wll get any images of Mercury's crescent phase though. Still, I was able to see the gibbous phase of Mercury. I've included a shot of an ealier apparition, which didn't work out so well.

Venus looks okay though (I'm still hanging out for a violet filter). If I can shoot an image a week I might be able to make a nice animation of Venus going into crescent phase (look at blog subtitle, yeah right).

The turbulence seemed less this time round, but Mars wasn't crisper. Not bad, but not a dramatic improvement. Here I contrasted stacking a 1 second AVI (30 frames) and a 2 second AVI (60 frames). Stacking was done in Registax. The only processing is tossing blurred frames and adjusting the wavelets to 10.5 (I have no idea what that means, I just do it and the image looks better). Given what was supposed to be in view (Sinus Meridiani), I'm pretty pleased at the level of detail I got.

This image is one of the 60 framers, stacked in Registax, resized with PaintShop Pro, gamma corrected to 0.8 to bring out more detail and an unsharp mask applied. It doesn't look to bad if I say so myself, but it is a bit artifical. I'll have another go tonight if possible.

Friday, November 04, 2005

Capturing Elusive Mercury

Mercury is the bright dot just near the roof in this image (click on the image to see a larger high definition view), Antares shines next to the crescent Moon and Venus blazes up high. After a fairly ordinary day weather wise the sky cleared up nicely, and I was able to see Mercury at it's greatest elongation from the Sun. After a rather delicious home made Pizza and while the others watched Strictly Dancing, I set up the scope and the camera. I shot of some images with the camera (including the one here) and turned to the scope.

My original plan was to get the focus sorted out on the Moon, then quickly shift to Mercury and get some quick shots before being called upon to go out and purchase icecreams. This plan did not take account of the hordes of particularly viscous mosquitoes lusting for my corpuscles. Now, normally mosquitoes ignore me, going for the more piquant flesh of my Bettdeckererschnappender weisle. However, this mob wanted me. After doing the mosquito slappping dance and mass mosquito destruction, I got Mercury in my scope moments before it disappeared behind the roof of the house next door. I'll process the shots later, but I doubt they will be exciting.

But again it was a beautiful might, with the crescent Moon cradling Earthglow, next to red Antares, Mercury glittering not far below. The only thing needed to make this a perfect night was a can of industrial strength mosquito replellent, the kind that melts plastic (and yes, the icecreams were delicious).

Looking to the edge of the Universe.

Thursday, November 03, 2005

Shameless Self Promotion

Astroblog will be featured in the upcoming December edition of Australia's popular science magazine Cosmos (which I have just added to my links section, am I a suck or what*), in Pandora, the "fun" section of the magazine.

Cosmos is also cool because it will publish a short story by my friend Chris Lawson. Don't know which issue it will turn up in though.

*I've been meaning to put it Cosmos and others in the links section for a while, really, but it took this to get me moving.

Housekeeping

Taking out the rubbish is a suburban ritual that is a microcosm of the heavens. Every week like celestial clockwork a green wheelie bin undergoes a short, highly eccentric but significant orbit from our yard to the kerb, and back again. Tonight while launching the big green bin on its orbit, I could see Venus, almost painfully bright, directly across from a very orange Mars. It was almost breath taking (and had a pleasing symmetry). Venus was burning near the the hook of the Scorpions tail, and all the stars in the tail were twinkling like crazy, so I knew it was a waste of time getting the scope out. Instead I just leant on my green companion and watched the sky peacefully.

Speaking of house keeping, I have changed the comments so that you have to type in a computer generated line of text to get your comment up (a couple of you have found out already the hard way). Sorry about the extra layer of annoyance, but I was getting tired of deleting premium dog food comment spam (everyone else gets interesting spam, I get dog food, I suppose this is a comment on my cosmic significance).

Also, if you scroll down you will note I've added some publications to my left hand links section, Sky & Space because it is a fantastic magazine for Southern Hemisphere amateurs (and I write for them, still, despite my near terminal ignorance of the concept of a deadline, they are forgiving people). The Australian Astronomy Almanac because it is an incredible reference that I use all the time (and I won bronze in their web-site Olympics). Finally, Cosmos, and Australian-based science magazine that covers a wide range of good science pitched at a general audience.

Finally, I have got the Southern Skywatch page for November finished. Putting together the Pleiades occultation times was a bit time consuming, as I do cities that don't turn up in the standard almanacs, but Astronomy goes on in the centre and north of Brisbane. Check it out for a feast of November Sky highlights.

Oh yeah, if you have just got back from holidaying in the Simpson Desert, you may not know that Pluto has two more moons. Read about it here, here and here.

Mercury In the Scorpions Head

Mercury is currently in the head of the Scorpion, tonight (Wednesday 2 November) it is 1 degree from delta Scorpii, giving it an extra "eye". On this Friday Thursday, November 4, Mercury will be at its greatest distance from the Sun, and will be at its most easy to observe. Look to the west shortly after local civil twilight (a bit over half an hour after sunset, you may have to wait a bit longer for distictive "T" shape of Scopius's head to be clearly visible). On this night the crescent Moon will also be very close to the red star Antares, so it will be a beautiful sight. The image shows what you would be likely to see roughly an hour after sunset, around nautical twilight, on the 4th.

Venus is also currently withing binocular range of lots of beautiful clusters, so will be a fine sight in binoculars.

[later edit], Yeah, I messed up my dates. And I've had more than 6 hours sleep twice in a row.

Tuesday, November 01, 2005

Venus and Mars were all right last night

Well, as I predicted the turbulence was pretty bad last night, at least the scope wasn't dripping with condensation though. The image shows last nights and the night before image, along with an image of what I should have been seeing at that time. I'm quite chuffed, despite imaging with a 320 x 120 elderly web cam, no clock drive and with the images dancing around in the turbulence, I can still clearly make out Syrtis Major, Hellas, Mare Serpentis and (just) Mare Cimmerium. The images were taken as 1 and 2 minute AVI's, and stacked with Registax after discarding the worst images. Tonight the weather has gone cludgy again, but if it clears up and the atmosphere settles down, then I'm going to see if I can get better resolution. One issue I do have is focus, in the absence of the Moon to get good focus, focusing on Mars is a right pain. I'm going to make myself a Hartmann mask to see if I can get better focus.

I also got a reasonable image of Venus as well, the image here is a time series showing Venus increasing in size and decreasing in phase. If all goes well I might be able to get the crescent phases of Venus. That would be something. I probably should get a wratten violet filter and go cloud hunting.